code: def test_pixelwise_softmax_derivative(backend_default):
      inputs = np.array([0, 1, 3, 1, 2, -2]).reshape((2, 3))
      outputs = np.ones((1, 6))
      inputs = inputs.reshape((1, -1))
      outputs = outputs.reshape((1, -1))
      compare_tensors(
          PixelwiseSoftmax(c=2), inputs, outputs, deriv=True, tol=1e-6
      )
  
imports: from math import tanh
  import numpy
  from neon import NervanaObject
  from neon.transforms import Identity, Rectlin, Softmax, Tanh, Logistic, Sign, PixelwiseSoftmax
  from utils import allclose_with_out
label_desc: Use image node_id 20 for calling a global function with example usage: test_pixelwise_softmax_derivative(backend_default) without return types